package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.Voucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import sun.awt.AppContext;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisWorker redisWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    // 使用Redis的Stream流来实现消息队列
    // private BlockingQueue<VoucherOrder> orderBlock=new ArrayBlockingQueue<>(1024*1024);
    private IVoucherOrderService proxy;
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandle());
    }

    private class VoucherOrderHandle implements Runnable {
        String queueName="stream.orders";
                
        @Override
        public void run() {
            while (true) {
                try {
                    // // 从阻塞队列获取订单
                    // VoucherOrder voucherOrder = orderBlock.take();
                    // // 创建订单
                    // handleVoucherOrder(voucherOrder);

                    // 获取消息队列中的订单消息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );

                    if (list == null || list.isEmpty()) {
                        continue;
                    }

                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);

                    handleVoucherOrder(voucherOrder);

                    // 确认ACK
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());

                } catch (Exception e) {
                    log.error("订单处理异常");
                    handlePendingList();
                }
            }
        }

        // 发生异常去阻塞队列获取订单数据
        private void handlePendingList() {
            while (true) {
                try {
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );

                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有消息，结束循环
                        break;
                    }

                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();

                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);

                    // 创建订单
                    handleVoucherOrder(voucherOrder);

                    // 确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());

                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                }
            }
        }
    }

   

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        // 多线程用户id不能从UserHolder中取
        // Long userId = UserHolder.getUser().getId();

        Long userId = voucherOrder.getUserId();

        RLock lock = redissonClient.getLock("lock:order:" + userId);

        boolean isLock = lock.tryLock();

        if (!isLock) {
            log.error("不允许重复下单");
            return;
        }

        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            lock.unlock();
        }

    }

    // 使用redis的stream流实现异步队列
    @Override
    public Result seckillVoucher(Long voucherId) throws InterruptedException {
        Long userId = UserHolder.getUser().getId();

        long orderId = redisWorker.nextId("order");

        proxy=(IVoucherOrderService) AopContext.currentProxy();
     
        // 放到redis的stream流中
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );

        int r = result.intValue();

        if (r != 0) {
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        
        
        return Result.ok(orderId);

    }


    // 使用java的阻塞队列实现异步下单
    // @Override
    // public Result seckillVoucher(Long voucherId) throws InterruptedException {
    //   Long userId=UserHolder.getUser().getId();
    //
    //     Long result = stringRedisTemplate.execute(
    //             SECKILL_SCRIPT,
    //             Collections.emptyList(),
    //             voucherId.toString(), userId.toString()
    //     );
    //    
    //     int r=result.intValue();
    //    
    //     if(r!=0){
    //         return Result.fail(r==1?"库存不足":"不能重复下单");
    //     }
    //    
    //     // 保存到阻塞队列
    //     VoucherOrder voucherOrder = new VoucherOrder();
    //     long orderId=redisWorker.nextId("order");
    //    
    //     voucherOrder.setId(orderId);
    //     voucherOrder.setUserId(userId);
    //     voucherOrder.setVoucherId(voucherId);
    //    
    //     orderBlock.add(voucherOrder);
    //    
    //     proxy=(IVoucherOrderService) AopContext.currentProxy();
    //    
    //    
    //     return Result.ok(orderId);
    //    
    // }


    //---------- 同步下单
    // @Override
    // public Result seckillVoucher(Long voucherId) throws InterruptedException {
    //     SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
    //    
    //     if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
    //         return Result.fail("秒杀尚未开始");
    //     }
    //    
    //     if(voucher.getEndTime().isBefore(LocalDateTime.now())){
    //         return Result.fail("秒杀已经结束");
    //     }
    //    
    //     if(voucher.getStock()<1){
    //         return Result.fail("库存不足");
    //     }
    //
    //     Long userId = UserHolder.getUser().getId();
    //
    //     // 一人一单----悲观锁,无法应对集群，也就是启动两台服务器，有两个jvm
    //     // synchronized (userId.toString().intern()){
    //     //     // 获取代理对象，这样就可以用到createVoucherOrder的事务
    //     //     IVoucherOrderService proxy =(IVoucherOrderService) AopContext.currentProxy();
    //     //     return proxy.createVoucherOrder(voucherId);
    //     // }
    //    
    //     // 分布式锁
    //     // SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
    //    
    //     // 使用Redisson分布锁
    //     RLock lock = redissonClient.getLock("lock:order" + userId);
    //
    //     boolean isLock=lock.tryLock(1L, TimeUnit.SECONDS);
    //    
    //     if(!isLock){
    //         return Result.fail("不允许重复下单");
    //     }
    //    
    //     try {
    //             IVoucherOrderService proxy =(IVoucherOrderService) AopContext.currentProxy();
    //             return proxy.createVoucherOrder(voucherId);
    //     }finally {
    //         lock.unlock();
    //     }
    //
    // }

    // 异步创建订单
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 一人一单
        Long userId = voucherOrder.getUserId();

        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();

        if (count > 0) {
            log.error("用户已经购买过一次");
            return;
        }


        // boolean success = seckillVoucherService.update()
        //         .setSql("stock=stock-1")            // 实现乐观锁，此方法虽然安全，但抢成功的概率较小
        //         .eq("voucher_id", voucherId).eq("stock",voucher.getStock()).update();

        boolean success = seckillVoucherService.update()
                .setSql("stock=stock-1")            // 实现乐观锁
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0).update();

        if (!success) {
            log.error("库存不足");
            return;
        }


        save(voucherOrder);

    }


    // 同步的创建订单
    // @Transactional
    // public Result createVoucherOrder(Long voucherId) {
    //     // 一人一单
    //     Long userId = UserHolder.getUser().getId();
    //    
    //     int count= query().eq("user_id",userId).eq("voucher_id", voucherId).count();
    //
    //     if(count>0){
    //         return Result.fail("用户已经购买过一次");
    //     }
    //
    //
    //     // boolean success = seckillVoucherService.update()
    //     //         .setSql("stock=stock-1")            // 实现乐观锁，此方法虽然安全，但抢成功的概率较小
    //     //         .eq("voucher_id", voucherId).eq("stock",voucher.getStock()).update();
    //
    //     boolean success = seckillVoucherService.update()
    //             .setSql("stock=stock-1")            // 实现乐观锁
    //             .eq("voucher_id", voucherId).gt("stock",0).update();
    //
    //     if(!success){
    //         return Result.fail("库存不足"); 
    //     }
    //
    //
    //     // 创建订单
    //     VoucherOrder voucherOrder = new VoucherOrder();
    //
    //     long orderId = redisWorker.nextId("order");
    //     voucherOrder.setId(orderId);
    //
    //
    //     voucherOrder.setUserId(userId);
    //
    //     voucherOrder.setVoucherId(voucherId);
    //     save(voucherOrder);
    //
    //     return Result.ok(orderId);
    // }
}
